He doesn't explain if it's ok for us to learn multiple languages or not, as according to the Bible it was intentional and deliberate that we couldn't communicate with foreign languages for a reason.
The ability to speak multiple languages is nowhere condemned in scripture. Many of the Jews in Jesus' day spoke Hebrew and Koine Greek.
The desired result was accomplished when God confused the language of the tower builders at Babel...it forced the language groups to separate and move away to populate other parts of the earth as God had instructed, taking ideas that originated with Nimrod with them. This is why we see a common thread running through all the world's cultures and religions....including a flood story....they have a common source.
We remember that when it was necessary to spread the gospel in the first century, God gave Jesus' disciples the ability to speak in all the languages of the foreign visitors who had come to Jerusalem for the festival.
One's mother tongue is the language of the heart.
Today, the language barrier has been well and truly crossed thanks to technology.
The prophet Zephaniah foretold that God would cleanse the earth....he reports God as saying.....
9 For then I will change the language of the peoples to a pure language,
So that all of them may call on the name of Jehovah,
To serve him shoulder to shoulder.’" (Zephaniah 3:8-9)
God's people will then all speak one language......
This is how many languages our website caters to....click on "English" in the top right hand corner.
https://www.jw.org/en/
There are hundreds!